The apparatus and process for transporting lithographic plates to a press cylinder described in this specification has particular (albeit not exclusive) application to management and handling of thin, flexible, lithographic printing plates in high rotational speed press operations.
An embodiment of an apparatus for transporting lithographic plates described herein is comprised of an indexer, a pod, and a pod elevator. Another embodiment of an apparatus for transporting lithographic plates is comprised of an indexer and a cart pod.
An embodiment of the process for transporting lithographic plates to a press cylinder most often operates in conjunction with an over-arching lithographic plate management and handling system. The system directs the operation of the indexer, pod, and pod elevator. Among other duties under its control, the system codes each plate. The code contains information, which the system PLC reads at various steps along the way of preparing lithographic plates for use on a printing press. The system uses the information to direct the plate along the correct and ultimate route to the printing press, including delivering the plate to an indexer, signaling the indexer to load the plate into various pod compartments, and using a pod elevator for transporting the plates to a press cylinder.
The indexer, pod, and pod elevator may be used to load, contain, and transport lithographic plates for web-offset printing, for non web-offset printing, or for non-printing applications. The operation of the indexer, the pod, and the pod elevator is described in this specification in conjunction with computerized system. However, the indexer, pod, and pod elevator may be operated without direction from a computerized system.
The web offset printing operation is highly automated. The heart of the operation is one or more high speed presses designed for efficient mounting and removal of lithographic plates. Each plate must be precisely mounted on the press' plate-mounting cylinder to ensure that the lithographic plate image is in exact registration, i.e., “square” with the press cylinder when in the manufacturer's locked-up position.
In addition to the high rotational speed press—the hub of the operation—the printing operation must have a high speed means of management and handling of the lithographic plates. Management and handling includes identification of each lithographic plate in the system and on-time transportation of the plate to the press or presses. The means of identification and transportation of plates includes a plethora of modules, of which an indexer, pod, and pod elevator are a part. Such modules may perform (a) imaging and processing of plates, including bar coding of each plate for identification purposes; (b) image to plate registration and plate to cylinder registration; (c) plate punching, bending, shearing, corner notching/cutting; (d) direction of work flow and plate traffic routing, including optical registration verification, plate inspection, bar-code scanning, and remote diagnostics; (e) on-time delivery of plates to the press, including sorting, stacking, and conveying the plates (using, for example, plate entry modules, rotators, indexers, stackers, crossover bridges, elevators, thru-the-wall transport modules, dual highway modules, auto plate feeders, dummy plate loaders, and conveyors; (f) plate storage (in pods or on stacking cart pods), delivery of pods to storage, and rack storing of pods; and (g) automated retrieval from storage of the indexed plates. The identification and transportation of plates (and the modules which carry-out these functions) must be synchronized with one another and with the press to ensure that the plates are transported to the correct place at the correct time and the various operations on the plates are done timely and properly.
The competitive, low-margin economics of the printing business requires that the press not only be high speed, but so must the management and handling of lithographic plates. In this environment, the plate management and handling infra-structure must be fast, efficient, automated, and reliable to complement the printing process and workflow environment. The plate management and handling system employed cannot be allowed to contribute to press down time and image register problems. The system must ensure the continuous process flow of press-ready, in-register plates for each press cylinder with repeatable results.
The embodiments of the lithographic plate management and handling system of the present invention and its automated and synchronized, modular components are designed to meet these goals by integrating the entire printing workflow into one efficient system. The lithographic plate management and handling system feeds the press with the lithographic plates. The integrated system is designed to fully automate plate management and handling and reduce operator involvement in the printing process and workflow environment, whether it be in-line or off-line. Such integrated system spans the photographic process of imprinting an image on a lithographic plate to locking up the plate on the press.
The embodiments of an indexer, pod, and pod elevator and the other components of the system are all designed to automate the workflow of a printing production environment and to produce press-ready plates for applications using different levels of press technology, multiple press types, and multiple press register requirements. No one printing operation is the same, so the indexer, pod, and pod elevator and the other components of system are designed to be flexible in design and configuration. They are designed to be an integrated system with the flexibility to be custom-configured in many different ways. Moreover, the indexer, pod, and pod elevator and the other components of the system described herein range from fully automated to un-automated, depending upon the needs of a particular user application.